Conventionally, an adsorption heat exchanger has been known, which includes a heat exchanger body for exchanging heat between a heat medium such as refrigerant and air, and an adsorbent layer formed on a surface of the heat exchanger body. The adsorption heat exchanger of this type is disclosed in, e.g., Patent Documents 1 and 2.
The adsorbent layer of the adsorption heat exchanger contains adsorbent absorbing moisture from air and dissipating moisture to air. As the adsorbent, inorganic material such as silica gel and zeolite, organic material having a hygroscopic property, etc. are used. In the adsorption heat exchanger disclosed in Patent Documents 1 and 2, the adsorbent is used, which is made of organic high-polymer material and which adsorbs and absorbs water vapor.
In the adsorbent disclosed in Patent Documents 1 and 2, a plurality of high-polymer main chains having hydrophilic polar groups are cross-linked to each other, and the plurality of high-polymer main chains cross-linked to each other form a three-dimensional structure. In the adsorbent, both of a phenomenon in which water vapor is adsorbed to the hydrophilic polar groups and a phenomenon in which water vapor is absorbed by the three-dimensional structure including the high-polymer main chains are occurred. As a result, the adsorbent traps a larger amount of water vapor as compared to, e.g., zeolite only adsorbing water vapor to a surface thereof.
A method for applying a mixture of powder having fine adsorbent particles and a solvent to the heat exchanger body and then forming the adsorbent layer on the surface of the heat exchanger body by evaporating the solvent is disclosed in paragraph 0055 of Patent Document 1 and paragraph 0053 of Patent Document 2.